While a user is watching a video using video streaming via network, if the user is interested in an image of the video or a part of the video, the user downloads the video in a storage device. Then the user captures the image or the part of the video from the stored video. If the network is poor, the video cannot be downloaded fast, and the quality of the video may be influenced, therefore, quality of a snapshot of the video is also influenced. Thus, the user cannot acquire a satisfied video snapshot. In addition, if the video is not downloaded completely as some segments in the video may be missed, the user cannot obtain a snapshot of the missed segments. And the user may not be given a choice to watch the video in different quality or resolution. Therefore there is room for improvement in the art.